A circuit breaker is used to protect an electric circuit from damage caused by a persistent overcurrent condition, short circuit, fault or other anomaly. During normal operation, mating contacts for each phase of the circuit breaker are kept in a closed position to enable current flow through the circuit. When a fault condition is detected, the contacts are automatically opened by an operating mechanism, thus interrupting the circuit and disengaging the circuit from a power supply (i.e., the circuit breaker is tripped).
The circuit breaker includes a housing having at least one accessory pocket configured for receiving a circuit breaker accessory. By way of example, an accessory switch may be located in the first accessory pocket. The accessory switch includes an accessory housing which accommodates an outwardly extending plunger that extends into the circuit breaker housing and engages a cross bar of the operating mechanism. The plunger is displaced by the cross bar when the breaker contacts are opened. This in turn actuates the accessory switch.
The plunger, which is a separate component from the accessory housing, is either attached by a pin or guided in a slot or a hole inside the accessory housing. The housing also accommodates a bias spring that resets the plunger when the plunger is not interacting with the circuit breaker mechanism. Such configurations require multiple parts (plunger, hinge pin, bias spring, and/or retaining hardware) which occupy space in the accessory housing.
However, the available volume within an accessory pocket is limited, thus constraining the size of the accessory housing. It is desirable to reduce the number of parts accommodated within the housing in order to make more space available in the accessory housing so as to provide additional design flexibility. In addition, it is desirable to reduce the number of parts in order to reduce tolerance stackups and assembly errors in order to reduce manufacturing costs.